A balance vehicle is also known as a somatosensory vehicle or a thinking vehicle. The operating principle thereof is mainly established on a basic principle called “dynamic stabilization”, the change of vehicle posture is detected by a gyroscope and an acceleration sensor inside the vehicle body, and a motor is accurately driven by a servo control system to adjust correspondingly, in order to keep the balance of the system.
The conventional balance vehicle has two frames opposite to each other and rotatable with respect to each other. A rotation coupling between the two frames are accomplished by a rotating mechanism mounted on both of the two frames. The two frames are joined with each other to form an integral structure. The location where the two frames are joined with each other of the conventional balance vehicle is only enclosed in a shell without using other assistant member to enhance an overall functional characteristic of the balance vehicle, which limits a development and utilization of the overall structure of the balance vehicle.